Hood cars are used in coke plants because of increasingly stringent environmental protection regulations in order to avoid as much as possible the release of fumes , dust and odor upon pushing of the coke, i.e. when glowing coke is pushed out of the hot oven chamber. The liberated emissions are drawn into the hood by the underpressure generated in the hood and are then drawn into the dedusting apparatus via exhaust channels and lines. Because of the high temperatures of the glowing coke each time a relatively large volume of gas has, during the pushing process, to be processed. Between the individual pushing steps air of normal temperature is drawn in and guided through the channels. During this process the walls of the exhaust channels cool down and result during the pushing process in a cooling of the hot, dust-laden gases.
It is known to hang tubes of a special material in the flow cross-sections of the exhaust channels, in order to increase this temperature effect. With the cooling of the exhaust gases, which enter at about 350.degree. to 400.degree. C. there is a volume decrease, which allows the following dedusting apparatus to be made smaller. A disadvantage is however that the tubes are composed of a special material and nearly fill the cross-section of the exhaust channels. Because of the high cost of this material and the need for a special process of manufacture these systems are disadvantageous. Since the gas flow passes through the individual tubes of relatively large length without turbulence, the larger dust particles carried over tend to deposit and in the long run clog up individual tubes.